Automatic trans. adjustment

[dsio]

I have a 1990 (january build) e34 525i with an automatic tran. The car seams to hold a lower gear far too long in rather easy and mild driving, and on the freeway, at 90Km/h, it should be going along in fourth, but you can feel it drop down to third far too easily if the road tilts up only slightly, or if you back off the throttle a bit.

It seams to want to stay around 1800-2600 all the time, and is using a bit more fuel than a 2.5 should be using. What is the best way to reduce its tendencey to drop a gear, and reduce the fuel usage at an expense of some power.

I notice that there is a sports / economy switch in some of these models, and from looking at the diagrams of the electronic side of the transmission, I can see that the AT computer, and the wiring harness for it are all pretty much the same. Would it be possible to fit one of these switches to this car using the wiring that is already present?

And given it has no switch, could it be in "sport" mode all the time, giving it the sharp feel it has at the expense of fuel economy?

[632 Regal]

try a reboot before switching things, you could have a faulty sensor telling the trans that it is cold even when it is hot.

[dsio]

Well, I dont really know how I would go about doing that. Could you explain it maybe? And also I still want to tweak it a bit and know how to do the adjustments if you could explain them. And is the sports/economy retrofit possible?

Thanks for the fast reply! When I ask questions about my E30 on other forums all I get is people telling me that my car is dying and I should sell all the parts off it to them for peanuts lol

[Kalevera]

The 4hp in the car doesn't have electric controls, so doing a reset to clear motronic adaptations probably wouldn't affect what is (likely) an internal valve body or torque converter hydraulic issue.

The first thing I would do is check stall speed.

best, whit

[Incantation]

you might also want to try disconnecting the throttle position sensor and see if it makes any difference. mine has been doing this too, except the shift points are different. it's annoying as fxck (pardon french) .. i got a new sensor and it wasn't it. i'm going to check if it's that hot/cold sensor thing

[Bill R.]

90 525 you have a kickdown cable for the accelerator, this cable could be out of adjustment.




I have a 1990 (january build) e34 525i with an automatic tran. The car seams to hold a lower gear far too long in rather easy and mild driving, and on the freeway, at 90Km/h, it should be going along in fourth, but you can feel it drop down to third far too easily if the road tilts up only slightly, or if you back off the throttle a bit.

It seams to want to stay around 1800-2600 all the time, and is using a bit more fuel than a 2.5 should be using. What is the best way to reduce its tendencey to drop a gear, and reduce the fuel usage at an expense of some power.

I notice that there is a sports / economy switch in some of these models, and from looking at the diagrams of the electronic side of the transmission, I can see that the AT computer, and the wiring harness for it are all pretty much the same. Would it be possible to fit one of these switches to this car using the wiring that is already present?

And given it has no switch, could it be in "sport" mode all the time, giving it the sharp feel it has at the expense of fuel economy?

[LynnSegal]

I had a similar problem. Believe it or not, it turned out to be under-inflated front tires...go figure...ls